Internet Chaos: Iberian Power Outage Disrupts Connectivity

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In an unanticipated series of events, a severe power outage struck a large section of the Iberian Peninsula on April 28, 2025. This blackout affected not only vast areas of Portugal and Spain but also extended its reach, albeit partially, to neighboring parts of France. Initiating at 10:34 UTC, the blackout brought everyday life to a standstill—paralyzing transportation systems, closing numerous retail businesses, and most critically, triggering major Internet connectivity disruptions. Initial reports suggested that the power failure originated from a fault within Spain’s electricity grid. The fault was allegedly caused by extreme temperature variations creating “induced atmospheric vibration” within very high voltage lines. Nonetheless, these allegations were subsequently refuted. Leveraging Cloudflare’s robust network infrastructure, a detailed examination of how this incident impacted Internet traffic and connectivity was conducted.

Impact on Portugal

Countrywide Disruptions

The sudden power loss in Portugal paved the way for a dramatic collapse in Internet traffic, as reports noted around a 90% plummet from normal levels within a mere five-hour timeframe. This decline was not just limited to everyday browsing but extended deeply into various online services, significantly affecting both businesses and personal Internet users. In tandem with this drop, traffic reaching Cloudflare’s 1.1.1.1 DNS resolver mimicked these patterns, initially seeing a sharp reduction of about 40%, which then continued to fall in the successive hours. These disruptions highlight the dependency of modern lifestyles and commerce on stable power and Internet services.

Network and Regional Variations

The repercussions of the blackout were swiftly evident at the network level, with local Portuguese Internet service providers such as NOS, Vodafone, MEO, and NOWO experiencing swift and significant reductions in traffic volume. Cloudflare Radar provided data showing a marked disappearance of activity from these networks shortly after the onset of the blackout, affecting both fixed and mobile broadband traffic. Interestingly, while MEO’s mobile network did experience a temporary surge in activity as users scrambled to mobile devices for information amidst the uncertainty, this usage too was ultimately reduced by half compared to the traffic levels from the preceding week. The blackout’s impact varied across regions, with major cities like Lisbon and Porto witnessing sharp, albeit limited, traffic decrease early on, followed by a nominal recovery. Contrasting this, areas such as Aveiro, Beja, and Bragança faced more abrupt and sharper drops in traffic with stabilization at significantly lower levels post the decline. However, a few regions like Braga and Setúbal observed a somewhat gradual decrease after the initial plummet.

Connectivity and Routing Declines

The power outage didn’t just influence traffic quantities but also gravely impacted the quality of Internet connectivity throughout Portugal. The country’s median download speed saw a significant decrease from around 40 Mbps to merely 15 Mbps during the outage. Latency rates also reflected this turbulence, jumping from a pre-outage level of 20 milliseconds to as much as 50 milliseconds. The deterioration in these network performance metrics likely resulted from the congestion of the remaining functional network links. Furthermore, the network infrastructure itself exhibited visible scars from the incident. A decrease in the announced IP address space indicated that particular segments of the national provider networks became entirely unreachable from the wider Internet. In numbers, the announced IPv4 address blocks (/24s) saw a shrinkage by about 300 blocks, which denotes approximately a 1.2% reduction. On the other hand, the announced IPv6 address blocks (/48s) faced an even more drastic reduction, declining from over 17 million to nearly 16 million. This drop represents a 9% decrease, continuing well beyond 16:00 UTC, correlating with the depletion of backup power supplies and the ensuing offline status of critical network infrastructure components.

Impact on Spain

Nationwide Internet Influence

Spain faced an Internet disruption scenario closely mirroring that of Portugal’s, displaying a significant drop in overall Internet traffic coinciding with the loss of power. Initial traffic levels dropped by 60% as reported and, across a span of five hours, reached depths of 80% below previously expected numbers. Likewise, DNS resolver request traffic retreated in a similar trend, initially retracting by 54% before settling. These statistics underscore the extensive geographical and demographic reach of the blackout’s impact within Spain, emphasizing the country’s vulnerability to sudden power and connectivity interruptions.

Regional and Network Plunge

An analysis of Spanish Internet service networks indicates that traffic from the leading five autonomous systems (ASNs) experienced a sharp and rapid nosedive coinciding with the blackout onset, sustaining a low level for hours thereafter. In contrast, a notable pattern emerged with Digi Spain Telecom (AS57269), which saw a quick initial traffic drop but managed to stabilize at reduced volumes later on. This underscores the region-specific dynamics and responsiveness observed during such disruptive events. Certain Spanish regions, specifically Navarre, La Rioja, Cantabria, and the Basque Country, showcased a measure of recovery potentially facilitated by swifter power restoration efforts as coordinated by Red Eléctrica, Spain’s grid operator. In regions including Catalonia, Aragon, the Basque Country, Galicia, Asturias, Navarre, Castile and León, Extremadura, Andalusia, and La Rioja, a partial revival of electricity was noted. This helped ameliorate the situation in some localities, though the impact of such an extensive outage continued to overshadow bits of relief.

Degradation of Network Quality

During the power outage in Spain, there was a marked contraction in the quality and speed of available Internet services. Prior to the blackout, the median download speed stood at approximately 35 Mbps; however, as the outage progressed, this metric fell precipitously to a lower threshold of 19 Mbps. Interestingly, the bandwidth’s decline exhibited non-linear patterns, bouncing from initial shocks before settling into a slower decreasing tempo. In parallel, latency experienced a significant escalation, doubling from 22 milliseconds to 40 milliseconds. This increase in latency metrics further suggested that networks were operating under stress, with remaining links experiencing elevated pressure and congestion. Additionally, a dip in the announced IP address space mirrored patterns seen in Portugal, with IPv4 address blocks (/24s) contracting by 2.4% by 14:30 UTC. The subsequent hours saw further reductions, while IPv6 address blocks (/48s) declined over 8% initially, with the downdraft persisting into later hours.

Ripple Effects in Europe

Broader European Repercussions

The ramifications of the Iberian blackout stretched far beyond Portugal and Spain, influencing parts of the wider European region in unforeseen ways. Among the directly affected territories was Andorra, though no notable disruptions were reported at any level there. Neighboring France, however, certainly experienced secondary effects, as French regional traffic observed minor reductions in alignment with the Iberian outage, although these were not as dramatic or prolonged and quickly recovered within 90 minutes. While Belgium reported cases of Internet impact, the causation did not explicitly address linkage to the Iberian power issue. Despite its continental distance, some ripples were noticed.

North African Influence

The power outage’s consequences were not confined to the European continent and made their presence felt in North Africa, with Morocco specifically reporting disruptions, as articulated by Orange Maroc. Network analytics via Cloudflare Radar highlighted that Moroccan Internet traffic encountered a pronounced dip accompanying the Iberian blackout, with disruptions around 12:00 UTC becoming more pronounced by 15:00 UTC. Though distant, the interconnectedness of global networks can sometimes denote significant ripples across even water-bound boundaries, revealing the complex dependency of networks stretching well beyond their geographic core.

Cloudflare’s Role

Monitoring and Mitigation

Cloudflare’s monitoring framework and infrastructure provided essential insights into Internet traffic, highlighting the robustness and resilience of the overarching internet ecosystem during the incident. By facilitating visualizations of traffic impact at both local and national scales, coupled with routing metrics, Cloudflare’s efforts embody proactive engagement in a world growing ever-reliant on Internet connectivity. Continuous monitoring through platforms like Cloudflare Radar remains a focal point in crisis responsiveness and network reliability assessments, ensuring broader stakeholder awareness of online dynamics throughout periods of turbulence.

Supporting Internet Resilience

Portugal recently experienced a sudden power outage, causing a dramatic decrease in Internet traffic. Reports indicate that there was about a 90% drop from usual levels within just five hours. This wasn’t limited to casual browsing; it affected various online services, impacting businesses and personal Internet users alike. The Internet’s reliance on a stable power supply was starkly highlighted as the disruption unfolded. Alongside this general decline, traffic reaching Cloudflare’s 1.1.1.1 DNS resolver followed a similar trend. Initially, it saw about a 40% drop, which continued to decline in the following hours. This situation underscores how crucial reliable power and Internet services are for modern life and businesses. The event is a reminder of our heavy reliance on digital connectivity. Without consistent electricity and Internet access, businesses can face disruptions leading to revenue losses, and individuals may struggle to perform daily tasks. The outage also emphasizes the importance of having contingency plans in place for such scenarios. As society becomes increasingly interconnected, ensuring uninterrupted power and Internet access is essential to maintaining our lifestyles and economic activities.

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